The present invention relates to off-road vehicles and, more particularly, to improvements in hydrostatic transmission and foot pedal controls for lawn and garden tractors and mowers.
Off-road vehicles of the prior art commonly employ two foot pedals, one foot pedal being used for a forward mode of vehicle travel and the other being used for a reverse mode of vehicle travel. In other arrangements, the prior art also employs a single foot pedal which can be utilized for both forward and reverse modes of operation of the vehicle. In the latter instance, such a foot pedal is pivotally mounted at a generally central portion thereof and can be pivoted i) for forward operation of the vehicle by an individual depressing a forward portion of the pedal with a forward portion of his or her foot, or ii) for reverse operation of the vehicle by being depressed at a rearward portion thereof by the operator's heel. The single foot pedals are also normally biased into a neutral central position to maintain the vehicle in neutral when the operator's foot is removed from the pedal.
A problem associated with the aforementioned single foot pedal type arrangement is that it may be uncomfortable for the operator to maneuver the pedal through its full range of motion. That is, the natural range of pivoting motion of an individual's foot about the ankle is normally not great enough to accommodate the required-range of pivotal motion of the foot pedal. In addition, the various surfaces of the pedal which must be engaged by the operator's foot are oftentimes arranged, positioned or angled in a manner which makes it awkward for the operator to operate. Another problem associated with such pedals is that debris, snow, mud, or the like, may become wedged between the vehicle floor plate, above which the pedal is mounted, and the underside of the pedal. As can be appreciated, any such substance which accumulates between the floor plate and foot pedal can have an adverse effect on pedal operation, especially in the reverse mode of vehicle operation.
It is therefore an object of the present invention to overcome the aforementioned problems. The present invention accomplishes this object by providing a mechanism for controlling the direction and speed of an off-road vehicle comprising a floor plate carried by the vehicle for receiving the heel portion of an operator's foot, and a pedal operatively connected to a variable speed transmission and pivotally mounted for movement between a forward zone for controlling the forward speed of the vehicle, a neutral zone wherein the vehicle is in a neutral mode, and a reverse zone for controlling the reverse speed of the vehicle. The pedal has first and second portions generally inclined with respect to one another and each are adapted for engagement by a forward portion of the individual's foot so that engagement of the first portion with a predetermined amount of force moves the pedal into its forward zone of movement, and engagement of the second portion with a predetermined amount of force moves the pedal into its reverse zone of movement. The pedal is arranged relative to the floor plate in a manner which enables the individual to selectively access the first and second portions with the forward portion of the foot by pivoting the heel of the foot on the floor plate, the pedal having at least the second portion thereof disposed outboard of a side edge of the floor plate.
Another problem that exists in such single pedal arrangements lies in their ability to smoothly and accurately return to the central neutral position after the operator removes his or her foot from the pedal. That is, in some instances, the centering mechanism of the foot pedal assembly of an off-road vehicle does not precisely locate and establish the hydrostatic transmission's neutral position (as determined by a hydrostatic transmission speed control input shaft to which the pedal is operatively connected), thus resulting in slight ground movement or creep in either the forward or reverse directions when the operator releases the pedal. In addition, there also exists a problem in that after the operator releases the pedal, the centering mechanisms of the prior art have a tendency to return the pedal to the central neutral position too quickly, thereby resulting in a jerking stoppage of the vehicle.
It is, therefore, another object of the invention to solve these problems by providing a control linkage for an input control of the input shaft of a hydrostatic transmission, the input shaft being rotatable between forward, neutral and reverse positions, the control linkage normally. maintaining the input shaft in the neutral position. The control linkage comprises an anchor brace, a lever connected to and pivotable about the control input shaft such that pivotal movement of the lever translates into rotational movement of the control input shaft, and a coil spring connected to the anchor brace and the lever. The connections between the coil spring and the anchor brace, the coil spring and the lever, and the control input shaft and the lever all lie in a single plane substantially parallel to a longitudinal axis of the input shaft when the shaft is in its neutral central position. At least one of the connections diverges away from the single plane as the input shaft diverges away from the neutral central position towards either the forward or reverse positions.
Another aspect of the present invention relates to a hydrostatic transaxle check valve normally provided in the aforementioned hydrostatic transmission type vehicles. Such check valves are used in switching the transaxle (or in a broader sense the vehicle as a whole) between a "drive" mode and a "push" mode. In the drive mode, the check valve is closed, and the hydrostatic transmission is hydrostatically locked to prevent the vehicle from moving when the vehicle motor is turned off. In the push mode, the check valve opens to permit the hydrostatic system to be in open flow and permit the vehicle to be manually pushed either in the forward or reverse directions. In the tractor and mower industry, there has been a need for a simple and inexpensive yet effective means for switching the hydrostatic transaxle check valve between the drive and push modes.
To meet this need, the present invention provides a switching mechanism for a hydrostatic transaxle check valve of an off-road vehicle, the off-road vehicle having a frame, a console, an operator seat, a steering wheel, an engine and a variable speed transmission coupled for driving at least one of a plurality of ground wheels. The hydrostatic check valve is push-button switchable between its opened and closed positions to convert the vehicle between its push and drive modes respectively. The switching mechanism comprises an operating rod movable between first and second positions. The switching mechanism has a manually engageable portion at a first end thereof, which manually engageable portion is normally disposed exteriorly of the console and beneath the seat. The seat is pivotable to permit manual access to the manually engageable portion. A cam member is provided and rotatable about an axis. The cam member has an eccentric portion capable of operational engagement with the push-button for switching the hydrostatic check valve between the opened and closed positions. In addition, a biasing member operatively couples the operating rod and the cam member, so that movement of the operating rod between the first and second positions causes rotation of the cam member in a manner which forces the eccentric portion into operational engagement with the push-button for switching the hydrostatic check valve between the opened and closed positions.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings, and the appended claims.